Power distribution system in a vehicle

ABSTRACT

The apparatus for energy distribution in a motor vehicle includes a vehicle electrical power supply system ( 11 ) with a generator ( 13 ) regulated by a voltage regulator ( 21 ), a battery ( 12 ) and consumers and a control arrangement ( 10 ) receiving required information from the power supply system for determining control parameters for engine or power supply system components. The control arrangement ( 10 ) includes the voltage regulator ( 21 ) and a supply system managing device ( 20 ). The supply system managing device ( 20 ) includes a device ( 24 ) for establishing an energy management strategy and a pre-control device ( 23 ) for generating a differential output for input to the device ( 24 ) according to an actual power and required power with respect to reference voltage. The pre-control device ( 23 ) and the device ( 24 ) for establishing an energy management strategy cooperate to determine a power supply set voltage (U_s) from the required information. The power supply set voltage (U_s) is compared with a measured actual voltage (U_ist) to produce a comparison results and the voltage regulator ( 21 ) regulates the generator according to the comparison result.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for energy distribution ina motor vehicle having a vehicle electrical power supply system with abattery and a generator and, more particularly, to an apparatus forenergy distribution in a motor vehicle having a vehicle electrical powersupply system with a battery, a generator regulated by a voltageregulator and a number of consumers and a control arrangement to whichrequired information is fed from t he vehicle electrical power supplysystem for determining control variables and regulating variables forcorresponding components of the vehicle electrical power supply systemand/or internal combustion engine. 2. Prior Art

At present, supplying power to electric consumers in a motor vehicleincreasingly presents a problem because the number and power consumptionof the electric consumers in the vehicle are constantly increasing. Atthe same time, the available energy that is generated by means of athree-phase generator regulated by a voltage regulator cannot beincreased to any desired extent because certain defaults or presets mustbe adhered to with respect to the size of the generator and its effectson the internal combustion engine driving it. In order to enable areliable power supply of the electric consumers, various measures arecurrently implemented which either lead to an increase in output in theelectrical energy delivered by the generator or which ensure thatelectric consumers which are not safety-related will be shut off atleast temporarily in the event of critical energy supply so as to enablea reduction in the electric energy to be made available.

An energy supply system for the electric consumers in a motor vehicle inwhich it is suggested to switch electric consumers depending on thedriving state is known from EP-0 601 300 B1. In the vehicle supplysystem described in this reference, the electric energy is generated ina conventional manner by a three-phase generator which is driven by theinternal combustion engine. In order to save fuel, the internalcombustion engine is turned off when the vehicle is stopped.Accordingly, no electric energy is generated by the generator duringthis time. On the other hand, in different driving states electricalenergy which is used to charge the vehicle battery and to supply theelectric consumers is generated in the customary manner. In order toachieve a reliable energy supply for operation-related electricconsumers regardless of the driving state, a strategy for supplyingelectric consumers is pursued with the aid of a control device whichcommunicates with various sensors and switches and which can influenceelectric actuators and display devices, wherein consumers are switchedon and off automatically when the control device detects certain drivingstates. The hierarchy in which consumers are switched on and off isselected in such a way that unessential consumers are switched off firstand consumers required for operation or related to safety are notswitched off at all. In certain driving states, the electric energy issupplied by the vehicle battery or by an auxiliary battery which isuncoupled from the vehicle battery.

In the known energy supply in a vehicle supply system, the drivingstates are assumed to be given and not subject to influence and, inorder to ensure adequate supply of energy to electric consumers, and itis stated only that groups of electric consumers are switched on or offcorresponding to the detected driving state. However, influence isexerted on the internal combustion engine depending on the requiredelectric output.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improvedapparatus for energy distribution to engine and power supply components,especially consumers, in a motor vehicle, which avoids or reduces theabove-described disadvantages.

This object and others, which will be made more apparent hereinafter,are attained in an apparatus for energy distribution in a motor vehiclehaving a vehicle electrical power supply system with a generatorregulated by a voltage regulator, a battery and a number of consumersand a control arrangement to which required information is fed from thevehicle electrical power supply system for determining control variablesand regulating variables for corresponding components of the vehicleelectrical power supply system and/or internal combustion engine.

According to the invention the control arrangement includes the voltageregulator and a vehicle power supply system managing means. The vehiclepower supply system managing means includes means for establishing anenergy management strategy and pre-control means, which cooperate todetermine at least one set value of the power supply set voltage fromthe required information with the help of a predetermined energydistribution strategy. The at least one set value of the power supplyset voltage is compared with a measured voltage to produce a comparisonresult and the voltage regulator regulates the generator according tothe comparison result. The voltage regulator and the pre-control meansare formed as separate units.

In contrast to the prior art, a further improvement in the supplying ofelectrical energy is achieved by the apparatus according to theinvention for energy distribution in a motor vehicle. At the same time,it is ensured that the battery charge level remains within a desiredrange. Further, an improved interaction between the generator, battery,vehicle drive or drivetrain and electric consumers is achieved. Voltagefluctuations in the electric power supply are advantageously reduced, sothat it is possible to achieve a voltage tolerance range which meets therequirements of especially sensitive consumers, for example, controldevices, in particular. Further, the reliability of the electric vehiclesupply system is advantageously increased and the design criteria forthe generator and battery are simplified in an advantageous manner.

These advantages are achieved in that an apparatus for energydistribution in the motor vehicle operates in such a way that theinternal combustion engine driving the generator as well as the electricconsumers of the vehicle supply system are taken into account in thedistribution strategy. For this purpose, the information supplied by thevehicle supply system and internal combustion engine is processed in acontrol arrangement for determining control variables and/or regulatingvariables and these quantities are supplied to the appropriatecomponents in the vehicle supply system or internal combustion engine.The energy distribution is then carried out by the control arrangementaccording to predeterminable requirements, taking into account thecondition that the actual voltage of the vehicle supply system lieswithin predeterminable limits.

The required information is advantageously obtained via suitable sensorsor state detectors and is supplied to the control arrangement. Thiscontrol arrangement acts, by way of determined control signals, ondifferent components of the vehicle supply system or on the internalcombustion engine itself. A differential output corresponding to thedifference between the required output with respect to reference voltageand the realized output is determined in an advantageous manner. Anactual voltage of the vehicle supply system can be determined from thisdifferential output. The vehicle supply system manager changes therequired output and/or the realized output in such a way that theresulting actual voltage of the vehicle supply system remains within thetolerance range.

In a particularly advantageous manner, the control arrangement whichcarries out the energy distribution is arranged as a vehicle supplysystem manager, wherein the energy management structure comprises avoltage regulator, pre-control and management strategy. The interactionof the generator, battery, drivetrain and electric consumers can bepredetermined by this energy management structure, wherein specialrequirements can be taken into account for this purpose. By means of thepre-control, it is possible to keep the vehicle supply system voltagewithin a narrow tolerance margin because the actual voltage given by thepreviously calculated differential output can be influenced by stepsimplemented by the vehicle supply system manager (so that it remainswithin the tolerance margin). Deviations from the reference voltage areadvantageously compensated by the voltage regulator.

Through the selection of a suitable management strategy, an idealcombination of energy generation, energy distribution and energyconsumption is given for the respective state of the vehicle, internalcombustion engine and vehicle supply system. In particular, when thebattery charge state is low, the speed of the internal combustion enginecan be increased; the generator can also be changed to an overexcitedoperation and/or electric consumer outputs can be reduced or electricconsumers which are not absolutely necessary can be entirely shut offwhen a deficit of power is detected.

By changing the vehicle supply system parameters, the drivetrain can berelieved in case full power is needed during acceleration of thevehicle. In this case, the generator torque loading the engine can bereduced by switching off higher consumers or by completely or partiallyuncoupling the generator. As long as the internal combustion engine isoperated in a state below full power, the loading generator torque canbe increased, wherein the additional load must be compensated throughregulation of the internal combustion engine.

Since the vehicle supply system manager allocates all relevant consumerpowers, it also influences the switch-on and switch-off behavior ofthese consumers; this also applies to duration with respect to time. Theswitch-on and switch-off behavior and the close coupling with the enginecontrol, for example, a torque requirement before switching on anadditional electric load, advantageously makes it possible to dispensewith the load-response function which is conventionally used to someextent at the present time, wherein load-response function signifies adelayed increase in generator current after high loads are switched on.Worst-case requirements on the generator, commonly used at the presenttime, can be reduced because the charge state can be maintained to thenecessary degree, when required, through steps such as reduction inconsumer power or increased speed and generator overexcitation.

The control arrangement and vehicle supply system manager can beconstructed as an independent control device which cooperates with thecontrol device of the internal combustion engine as well as with thecontrol part of the voltage regulator, wherein corresponding connectionsand interfaces must exist. However, the vehicle supply system managercan also be a component part of the vehicle control device or can beintegrated in an intelligent voltage regulator, wherein the connectionbetween the internal combustion engine control device and the voltageregulator must be constructed in a suitable manner. The vehicle controldevice can also take over all of the functions of the vehicle supplysystem manager.

BRIEF DESCRIPTION OF THE DRAWING

The objects, features and advantages of the invention will now beillustrated in more detail with the aid of the following description ofthe preferred embodiments, with reference to the accompanying figures inwhich:

FIG. 1 is a block diagram of an apparatus according to the invention forenergy distribution in a motor vehicle having a vehicle electrical powersupply system and a control arrangement for managing distribution ofelectrical power to components of the vehicle supply system and theinternal combustion engine;

FIG. 2 is a block diagram of the vehicle power supply system manager;

FIG. 3 is a block diagram of the control arrangement according to theinvention including the energy management strategy means and pre-controlmeans; and

FIG. 4 is a block diagram of part of another embodiment for managingdistribution of electrical power including a navigation system.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

TABLE 1 Definition of abbreviations used in FIGS. 1 to 3 BN vehiclesupply system BZ battery state BZE battery state detection (calculationor measurement) ΔP_gen change in output to be realized by the generatorΔP_sV change in output to be realized by consumer management FZinformation about future driving cycle G_s parameter vector forgenerator control, e.g., control of pulse inverter GZ generator stateGZE generator state detection (calculation or measurement) I_err excitercurrent M_f torque requirement of drivetrain on vehicle supply systemM_mot_anf torque requirement of vehicle supply system on drivetrainn_mot speed of internal combustion engine n_s speed demand of vehiclesupply system on drivetrain with the aim of changing the generatorspeed, i.e., change in generator transmission ratio is also possible.P_Bat battery output P_diff differential output = demanded output inrelation to reference voltage − realized output P_f power requirementP_Gen electric generator output P_nsV_Us power of non-controllableconsumers in relation to reference voltage − realizable output P_stellregulator output value (actuating variable), power indication P_sV_Usallocated power of controllable consumers in relation to referencevoltage Reg_s parameters for regulator control, e.g., for stopping theintegrator t_s allowed switching time (time in which the demanded outputmust be realized) U_ist actual voltage of vehicle supply system U_sreference voltage of vehicle supply system For FIG. 4: U_Bat batteryvoltage I_Bat battery current T_Bat battery temperature T_F drivingperiod Str type of road (highway, rural road, city) Z_Str state of road(traffic volume, . . . ) Z_Bat battery state (very critical, critical,satisfactory, good) = BZ LZ battery charge state N_11:S idling referencespeed n_schalt_s switching thresholds of transmission control P_veravailable consumer power n_zuk vector of future average available speedwith components n_kurz: short-term speed availability n_mittelmedium-term available speed n_lang long-term available speed

FIG. 1 shows the energy management structure making possible the energydistribution between the vehicle supply system and the internalcombustion engine or motor. The control arrangement 10, also referred toas vehicle supply system manager, is responsible for the energydistribution. This control arrangement is essentially a microprocessorwith a central processor unit, not shown, and storage means andinput/output means by which the signals can be supplied and emitted. Thecontrol arrangement 10 determines from the information that is supplied,for example, by suitable sensors or state detection devices and thelike, the control signals which can be supplied to the individualcomponents. Reference is had to Table 1 with regard to theabbreviations.

The coupling of the vehicle supply system manager formed by the controlarrangement 10 to the vehicle supply system and the relevant drivetrainis represented in FIG. 1 as a block diagram. With respect to the vehiclesupply system 11, including the drivetrain relevant to the vehiclesupply system, FIG. 1 shows the battery 12, the generator 13, the unitcomprising engine and transmission 14, a switch group 15, a summationpoint 16 and a block 17 in which a function of the differential outputto be defined hereinafter is formed. In addition to the vehicle supplysystem 11, a battery state detector 18 and generator state detector 19are also shown. The blocks are interconnected by arrows showing theinput or output of quantities which are defined more fully in Table 1.The direction of the arrows determines the signal direction.

The following signals and information are fed to the control arrangement10 and vehicle supply system manager: The demanded power P_f, thepermissible switching time t_s, meaning the time in which the requiredoutput must be realized; information about the driving cycle, the enginespeed M_f, the torque requirement of the drivetrain on the vehiclesupply system M_f, information about the generator state GZ which isobtained by means of the generator state detector shown in block 19.Further, information about the battery state obtained in the batterystate detector 18 is supplied to the vehicle supply system manager and,finally, the vehicle supply system actual voltage U_ist required forregulation of the generator voltage is also supplied. The optimum energydistribution is calculated and the control signals required for this areformed based on the quantities indicated above as well as on furtherinformation, if required, and/or based on data or characteristic fieldsstored in the storages of the control arrangement 10. These controlsignals are sent by the control arrangement 10, that is, by the vehiclesupply system manager. In particular, these control signals are: avehicle supply system reference voltage U_s which is supplied to thebattery 12, an exciter current I_err which can be predetermined, and aparameter vector for generator control, for example, for controlling thepulse inverter of the rectifier bridge G_s belonging to the generatorand supplied to the generator 13. A speed request addressed to thedrivetrain by the vehicle supply system is sent to the engine andtransmission 14 with the aim of changing the generator speed, ifnecessary also by influencing the generator transmission ratio n_s;further, a torque requirement M_mot_anf addressed to the drivetrain bythe vehicle supply system is sent to the engine and transmission 14. Theallotted power of the controllable consumers with reference to thereference voltage P_sV_Us is supplied to the summation point 16. Thedifferential output P_diff, which is the demanded power with respect tothe reference voltage minus the realizable output, is formed by theallotted power and other outputs which can be supplied.

In order to determine the theoretical differential output in the vehiclesupply system manager, the vehicle supply system is simulated by way ofa model. This procedure is described with reference to the real vehiclesupply system (FIG. 1). The actually supplied generator output P_Gen,the output P_Bat actually delivered by the battery, the demanded powerof the controllable consumers at reference voltage P_sV_Us and thedemanded power of the non-controllable consumers at reference voltageP_nsV_Us are supplied to the summation point 16. There is always anpower equilibrium in the vehicle supply system, that is, generated poweris equal to consumed power. The generated power as well as the consumedpower depend on the actual voltage. When the delivered power differsfrom the demanded power at reference voltage, the actual voltage of thevehicle supply system is adjusted in such a way that the consumer powerat actual voltage is equal to the generated power. This is shown by thefunction in block 17. This voltage change is calculated beforehand inthe vehicle supply system manager before changes are made to the vehiclesupply system state, for example, before consumers are switched. If theprior calculation shows that the actual value of the vehicle supplysystem lies outside of the tolerance range after the changes have beenrealized in the vehicle supply system, the vehicle supply system managertakes steps to prevent this.

Another arrow shown between the engine and transmission 14 and thegenerator 13 symbolizes that the motor speed or internal combustionengine speed n_mot is essential for the operation of the generator 13.As is known, the generator 13 is driven by the engine 14, possibly via atransmission. The achievable generator speed is accordingly correlatedwith the engine speed, possibly taking into account a transmission, ifpresent. The dependency of the generator speed on the engine speed canbe influenced by influencing the transmission.

The energy management according to the invention is realized by means ofthe vehicle supply system manager contained in the control arrangement10 based on the quantities and relationships indicated in FIG. 1. Thevehicle supply system manager operates the generator 13, the battery 12,the drivetrain, in particular the motor and transmission 14, and theconsumers of the vehicle which are not shown in more detail in FIG. 1,so that, on the average, a balanced charge state is ensured in thevehicle supply system and the voltage position is maintained within aspecified range or margin.

The vehicle supply system manager decides about a suitable strategy forthe generation and distribution of power based on the battery state, thegenerator state, the drivetrain state, the vehicle supply systemvoltage, or battery voltage, and the required electrical power. In sodoing, controllable electric consumers are distinguished fromnon-controllable electric consumers, wherein the latter constitute anelectric load which cannot be influenced. These consumers are thosewhich may not be switched off under any circumstances because they areabsolutely necessary for the proper functioning of the overallarrangement.

The vehicle supply system manager allocates the available electric powerto the controllable electric consumers. This allocation includesswitch-on behavior and switch-off behavior as well as the times forswitching on and switching off. Further, the vehicle supply systemmanager also gives the relevant quantities for the generator control.For example, the exciter current which is supplied to the exciterwinding of the generator is adjusted by the vehicle supply systemmanager, wherein the prevailing conditions are taken into account. Thevehicle supply system manager calculates an optimum vehicle supplysystem reference voltage and compares it with the actual voltage and, byway of suitable connections, can influence parameters which determinethe generator speed.

FIG. 2 shows the essential parts of the vehicle supply system manager inmore detail. The control arrangement is designated as vehicle supplysystem management plus pre-control. The following input quantities aresupplied to the vehicle supply system management plus pre-control: thetorque requirement of the drivetrain and vehicle supply system M_f, thepower requirement P_f, the allowed switching time t_s, that is, the timein which the required power must be realized, information about thefuture driving cycle, FZ, an actuating variable supplied by theregulator 21 which, as regulator output quantity P_stell, contains anoutput statement. Further, the vehicle supply system actual voltageU_ist, information about the battery state BZ, the generator state GZ,and the speed of the internal combustion engine n_mot is also supplied.

Proceeding from the quantities mentioned above as well as additionalquantities, if required, the vehicle supply system management pluspre-control determines the control quantities required for energymanagement and energy distribution and sends them to the appropriatecomponents of the vehicle supply system and the motor itself viaconnections.

The output quantities sent by the vehicle supply system management pluspre-control are: the allotted power of the controllable consumers withrespect to reference voltage P_sV_Us, the speed requested of thedrivetrain by the vehicle supply system with the aim of changing thegenerator speed, possibly also by changing the generator transmissionratio n_s, torque requirement of the vehicle supply system drivetrainM_mot_anf, exciter current I_err, parameter vector for generatorcontrol, for example, for controlling the pulse inverter G_s, vehiclesupply system reference voltage U_s. Further, the output quantitycomprising the parameters Reg_s for regulator control, for example, forhalting the integrator integrated in the regulator, is sent to theregulator 21. The vehicle supply system reference voltage U_s is fed toa summation point 22 communicating with the input of the regulator 21and is superposed therein with the vehicle supply system actual voltageU_ist for forming a voltage-dependent input quantity for the regulator21.

The determination of the output quantities of the vehicle supply systemmanager is explained with reference to the relationships shown in FIG.3. In the block diagram according to FIG. 3, a first block 23 designatesthe pre-control, to which is supplied information respecting the batterystate and generator state. Further, the engine speed n_mot, the vehiclesupply system actual voltage U_ist, the power requirement P_f and thevehicle supply system reference voltage U_s are supplied to thepre-control 23. These quantities are measured or determined by means ofsuitable detection means. They are used for the pre-control 23 to formthe differential output P_diff which corresponds to the differencebetween the required power with respect to reference voltage and therealized power.

The differential output determined in the pre-control is supplied toblock 24, the management strategy, including a battery management asfirst input quantity. Additional input quantities of block 24 of themanagement strategy are: the output quantity of the regulator (block 21)P_stell, the torque demand made by the drivetrain on the vehicle supplysystem M_f, the engine speed n_mot, the power requirement P_f, theallowed switching time t_s, that is the time in which the required powerP_f must be realized. Further, information about the future drivingcycle FZ as well as information regarding the battery state andgenerator state is supplied to block 24 of the management strategy.

Depending on the supplied information and on the differential outputdetermined in the pre-control 23, control signals for the voltageregulator Reg_s are supplied to the management strategy in block 24.These signals represent parameters for regulator control, for example,for stopping the integrator integrated in the voltage regulator.

The change in output to be realized by the generator ΔP_gen is suppliedas additional output quantities of the management strategy 24 to block25 which represents the generator control, including the generatordrive. Essential quantities for the generator are determined in thisblock 25. For example, these quantities are the exciter current I_err, aparameter vector for the generator control G_s which is used, forexample, for controlling the pulse inverter of the generator. Further,the speed request is sent to the drivetrain by the vehicle supply systemn_s with the aim of changing the generator speed, wherein a change inthe generator transmission ratio can also be contained in this signal.Finally, the torque requirement is sent to the drivetrain by the vehiclesupply system M_mot_anf. In another block 26, the consumer control iscarried out. For this purpose, the change in output ΔP_sV which is to berealized by way of the consumer management is reported in block 26 bythe management strategy 24. The vehicle supply system reference voltageU_s is supplied by the management strategy 24 to the generator control25 on the one hand and to the consumer control 26 on the other hand andis available for further evaluation devices as an individual signal.

Depending on the vehicle supply system reference voltage U_s and thechange in output ΔP_sV which is to be realized by way of the consumermanagement, the consumer control determines the allotted power of thecontrollable consumers with respect to the reference voltage P_sV_Us.Depending on this allotted power, the controllable consumers areswitched on or off by the vehicle supply system management.

As is shown in FIGS. 2 and 3, the vehicle supply system manager isformed of two main blocks, the regulator 21 and the vehicle supplysystem management and pre-control block 20. The pre-control calculatesthe output difference to be adjusted from the realized electric outputand required future output. Accordingly, the following calculation iscarried out: P_diff=P_gef−P_real. The occurring difference must becompensated through steps undertaken by the vehicle supply systemmanager until the required power is allocated so as to prevent orminimize a voltage dip in the vehicle supply system It must be ensuredthat the specified voltage tolerance margin is not departed from.Possible steps for adapting output include, for example, manipulation ofthe generator excitation or changing the power allocation for determinedconsumers. These steps must be introduced in case the vehicle supplysystem manager determines that the desired energy distribution posesproblems.

Deviations from the reference voltage due to an inexact estimation ofthe output to be realized in the future are compensated by the voltageregulator. Its actuating variable, the change in output, is an inputquantity of the management strategy which decides how the change inoutput is to be realized.

Within the framework of the management strategy, the vehicle supplysystem reference voltage which is essentially determined by the desiredbattery voltage is determined in addition. Due to the interaction of theenergy management structure comprising the regulator and the pre-controland management strategy, the interaction of the generator, battery,drivetrain and electric consumers can be adapted to predeterminabledesired processes. By means of the pre-control to which the actualvoltage is also always supplied, it is possible to keep the vehiclesupply system voltage within a narrow tolerance margin. Deviations fromthe reference voltage are compensated by the regulator 21.

As a result of a suitable management strategy, the ideal combination ofenergy generation, energy distribution and energy consumption is given.Suitable steps are, for example, an increase in the engine speed,especially the idling speed in the event of a low battery charge oroverexcitation of the generator under conditions which do not lead toheavy loads, for example, thermal loading. It is also possible to switchoff uncritical consumers in the event of deterioration of the batterycharge state. Similarly, the generator torque loading the engine duringacceleration of the vehicle can be reduced by uncoupling the generatoror by switching off consumers. The strategy carried out for energydistribution can be predetermined and is taken into account by thevehicle supply system manager.

A possibility for expanding the previously described energy managementshould be described in the following with reference to FIG. 4. In FIG.4, an embodiment form is shown in which a navigation system which isalready available in many vehicles in any case is taken into account indetermining the anticipated driving cycle FZ. This navigation systemsupplies a large amount of information which can be taken into accountin estimating the anticipated future engine speed.

The navigation system is designated by 27 in FIG. 4. It deliversinformation about the driving duration T_F, the type of road Str(highway, country road, city) to be expected in the near future, andinformation about the state of the road Z_Str taking into account theexpected traffic volume. The information available to the navigationsystem is used in block 28 to estimate future average engine speed. Thespeeds expected over the short term, medium term and long term can bedetermined. In block 28, a vector n_zuk is formed for estimating thefuture average engine speed which serves as a vector of the futureaverage available speed and has components n_kurz. These components haveto do with the available speed anticipated over the short term. The samekind of vector can be formed for the medium-term available speedn_mittel and the long-term available speed n_lang. The vectors formed inthis way are taken into account in block 29 in the evaluation of thebattery state. For optimum evaluation of the battery charge state,information about the battery charge state LZ is supplied in block 29and is determined in the battery charge state detector 30. The batterycharge state detector 30 evaluates, for example, the battery voltageU_Bat, battery current I_Bat, battery temperature T_Bat and, ifnecessary, additional quantities.

In the evaluation of the battery state in block 29, a battery stateZ_Bat is determined as a function of the battery charge state,anticipated speed and possibly additional anticipated quantities. Thebattery state Z_Bat is supplied to the energy management 31. The batterystate Z_Bat can be defined, for example, by four states (very critical,critical, satisfactory, good). Depending on these states, the energymanagement 31 regulates the entire energy distribution of the vehicleand vehicle supply system. For this purpose, the energy management 31gives control signals to corresponding components, for example, anidling reference speed n_(—) 11_s, switching thresholds of thetransmission control n_schalt_s, available consumer power P_ver, etc.

By taking into account information obtained from data of the navigationsystem with respect to estimating future average engine speed, it ispossible to take into account the expected speed in the energymanagement. Accordingly, it is possible initially to dispense with anincrease in the engine speed in the event of a low charge in case theestimation of the future engine speed indicates that an increased speeddemand is expected, for example, as a result of highway driving.Unnecessary increases in speed can be avoided with a procedure of thiskind and accordingly unnecessary fuel consumption can be reduced. Inestimating the battery state, the current charge state can always beevaluated in connection with the future available speed and appropriatesteps can be instituted. A low charge state when traffic jams areexpected is evaluated as more critical than the same charge state inconnection with highway driving with high available speed. If noinformation is known about the future driving cycle, the worst case mustbe assumed and steps must be initiated for improving the battery chargestate when falling below an established charge state threshold. Theabove-mentioned steps, including switching off electric consumers,increasing the idling speed, manipulating the transmission control tospeed level, etc. must be taken. These steps lead to a higher fuelrequirement or to a loss of functionality. They can be avoided byevaluating the information supplied by the navigation system.

What is claimed is:
 1. An apparatus for energy distribution in a motorvehicle having an internal combustion engine (14), said apparatuscomprising a vehicle electrical power supply system (11) including agenerator (13) regulated by a voltage regulator (21), at least onebattery (12) and a plurality of consumers, said generator (13) beingdriven by said internal combustion engine (14), and a controlarrangement (10) to which required information is fed from the vehicleelectrical power supply system for determining control variables andregulating variables for corresponding components of at least one of thevehicle electrical power supply system and the internal combustionengine (14); wherein said control arrangement (10) comprises means forenergy distribution management between the electrical power supplysystem and the internal combustion engine according to predeterminedrequirements so that a power supply set voltage (U_s) is kept withinpredetermined limits; and wherein said control arrangement (10)comprises said voltage regulator (21) and a vehicle power supply systemmanaging means (20), said vehicle power supply system managing means(20) including means (24) for establishing an energy management strategyand pre-control means (23) for generating a differential output (P_diff)from at least a part of said required information, said differentialoutput being input into said means (24) for establishing an energymanagement strategy and corresponding to a difference between actualpower and required power with respect to a reference voltage, so thatsaid means (24) for establishing an energy management strategy and saidpre-control means cooperate with each other to determine at least oneset value of the power supply set voltage (U_s) from said requiredinformation with the help of a predetermined energy distributionstrategy, as well as means (22) for comparing said at least one setvalue of the power supply set voltage (U_s) with a measured voltage(U_ist) to provide a comparison result; and wherein the voltageregulator (21) includes means for generating a power adjusting parameter(P_stell) according to said comparison result and means for regulatingsaid generator (13) according to said power adjusting parameter; andsaid voltage regulator and said pre-control means are formed as separateunits.
 2. The apparatus as defined in claim 1, wherein said controlarrangement (10) is a microprocessor independent and separate from saidvoltage regulator (21) or a control device of the internal combustionengine.
 3. The apparatus as defined in claim 1, wherein said controlarrangement (10) is a microprocessor integrated in said voltageregulator (21) or a control device of the internal combustion engine. 4.The apparatus as defined in claim 1, further comprising a battery statedetector (18) and a generator state detector communicating with thevehicle power supply system managing means (20).
 5. The apparatus asdefined in claim 1, wherein said voltage regulator (21), said means (24)for establishing an energy management strategy and said pre-controlmeans (23) are separate and independent devices.
 6. The apparatus asdefined in claim 1, wherein said vehicle power supply system managingmeans (20) includes a generator controller (25) and a consumercontroller (26) and said means (24) for establishing an energymanagement strategy (24) generates control signals for said generatorcontroller (25) for controlling said generator (13) and other controlsignals to said consumer controller (26) for generating consumercontrolling signals.
 7. The apparatus as defined in claim 1, whereinsaid vehicle power supply system managing means (20) includes means foroptimizing electrical energy distribution from said requiredinformation, said required information including a power requirement(P_f), an allowed switching time (t_s) in which a required power levelmust be reached, a battery state (BZ), a generator state (GZ), ameasured voltage (U_ist) of the vehicle power supply system, a torquerequirement (M_f) of a drive train on the vehicle power supply system, adriving cycle (FZ), an engine speed (n_mot) and said power adjustingparameter (P_stell).
 8. The apparatus as defined in claim 7, whereinsaid vehicle power supply system managing means (20) includes means forgenerating at least one output signal for a variable selected from thegroup consisting of said power supply set voltage (U_s), a parametervector (G_s) for generator control, a parameter vector of a pulseinverter of a rectifier bridge for said generator, a torque requirementon a drive train (M_mot_anf) of the motor vehicle and a speedrequirement on said drive train for changing generator speed, takinginto account a generator transmission ratio (n_s) and power requirementsof non-controllable consumers in relation to another reference voltage(P_nsv_Us).
 9. The apparatus as defined in claim 1, wherein said vehiclepower supply system managing means (20) includes a navigation system(27) with means for outputting data regarding driving duration and stateand type of a road traveled by said motor vehicle as well as an expecteddriving cycle and said control arrangement (10) includes means (28) forestimating a future average engine speed based on said data from saidnavigation system (27).
 10. The apparatus as defined in claim 9, furthercomprising means for evaluating battery charge state according to saidfuture average engine speed.